Summary of Findings
Our study evaluated 165 MPH dissertations. Although the overall reporting quality was relatively good, some essential aspects of methods and results were seldom reported, which makes it difficult for readers to assess the validity and reliability of an observational study [16]. Moreover, dissertations of superior reporting quality usually contained the following predictive factors: cohort study, funding support and more papers published during the postgraduate period.
Reporting on the title and abstract section and the introduction section was satisfactory. The reason may be that each MPH candidate needs to undergo strict opening and midpoint screening stages in the early stage of the dissertation writing. The deficiency of the reporting of MPH dissertations occurred mainly in methods and results. In particular, there was a need for dissertations to improve their reporting of variable definitions, statistical methods, and flow diagrams.
In actual studies, the outcome, exposure, predictors, potential confounders, and effect modifiers of the study should be clearly defined, but less than half of the dissertations fully reported these contents. Inadequate reporting of statistical methods may indicate that the research results are not fully exploited, resulting in a waste of valuable information and varying degrees of bias. However, only a few articles described any methods used to examine sub-groups and interactions, explained how missing data were addressed, and described any sensitivity analysis. Only 25 dissertations (15.15%) used flow diagrams, while others did not take advantage of the simple and direct features of the flow diagram. In addition, all of the articles summarized the key results with reference to the study objectives, but only approximately one-quarter of the articles discussed the generalizability of the study results.
The results of the multivariate logistic regression analysis indicated that funding support was associated with high reporting quality. To receive funding, projects require rigorous research designs and need to be screened and approved. Therefore, masters candidates are strictly required and trained to learn more knowledge to ensure that their thesis quality will be higher. Moreover, a positive association between more papers published during the postgraduate period and high reporting quality was observed. Masters candidates who published more papers during the postgraduate period have stronger academic ability, are more familiar with writing articles, and know what should be reported in detail. In addition, the results of the univariate logistic regression analyses showed that a higher number of statistical methods was associated with high reporting quality. Masters candidates who use more statistical methods have a deeper understanding of methodology, are more proficient in using statistical methods, and tend to be more complete in reporting their methods in their dissertations.
Compared with other studies
A few articles have evaluated the reporting quality of observational studies in other medical disciplines. Several studies have found that the reporting quality of articles that used the STROBE statement for standardization was better than that of others [19, 20, 25, 26]. Jacqueline Ramke et al. used the STROBE statement to evaluate reporting in blindness prevalence surveys and found that the mean of the STROBE score of studies published in journals requiring the STROBE statement was higher than that for others [19]. Swords C’s study indicated that the STROBE statement had increased the reporting quality of observational otology and audiology studies [20]. Hence, we strongly recommend that masters candidates should be familiar with the STROBE statement.
On the other hand, many studies have found defects in reporting the methods and results of observational studies [27-29]. Adams AD et al. discovered poor reporting in obstetrics observational studies for study size, missing data, and absolute studies [27]. Karaçam Z evaluated the reporting quality of observational studies in Turkish nursing journals and found that methods sections were mostly omitted [29]. Our research yielded similar results.
Educational implications
Our study has highlighted the important deficiencies in the reporting of observational studies in MPH dissertations. Based on these findings, we believe that if universities adopt the STROBE criteria to guide MPH candidates, it will help improve the reporting quality of MPH dissertations. In the course of master training, it is necessary to strengthen students’ understanding and flexible application of statistical methods, and graduate tutors should pay more attention to masters students who published fewer papers during the postgraduate period.
Strengths and limitations of this study
As a systematic review of MPH dissertations, our study has some advantages. First, it is a comprehensive assessment and used logistic regression analyses to identify factors associated with high-quality reporting. For the evaluation of dissertations, we included not only adherence to STROBE items but also the STROBE score. Second, some of the evaluation items, such as 6b and 14c, are not applicable to all dissertations, and some items are not adequately reported. To minimize biases against systematic review, we identified items as fully reported, partly reported, not reported, and not applicable and assigned the scores accordingly. Thus, different articles have a more consistent score criterion. Third, since the STROBE statement was published in 2007, no studies have used this guideline to evaluate the reporting quality of master dissertations. Therefore, our work is innovative and will provide a reference for subsequent similar research. Fourth, the study includes the independent assessment of all articles by two authors. All details of our search are transparent and clearly stated, and it can therefore easily be reproduced.
There are also some limitations of this study. First, the scoring of items remains a subjective task and easily leads to subjective bias. However, the two investigators independently used the STROBE statement to evaluate the included studies, and differences were resolved by discussion. In this way, we minimized subjective bias. Second, given that our research was restricted to MPH dissertations published by Chinese masters candidates in the past five years, the results reflect only the integrity and standardization of the reporting of Chinese MPH dissertations to a certain extent. Finally, since there is no literature to be found on using the STROBE statement to evaluate the reporting quality of medical masters dissertation, it is impossible to compare the reporting quality of these dissertations with that of dissertations in other professions.